Methods and apparatus for adjustable surfaces

ABSTRACT

Methods and apparatus for systems having deployable elements according to various aspects of the present invention comprise a system including a deployable surface and an adaptive actuator including a polymer foam. In one embodiment, the system comprises a vehicle including a deployable wing comprising an exterior surface. The exterior surface may be adjusted by adjusting the shape, size, position, and/or orientation of the adaptive actuator.

This is a continuation of U.S. application Ser. No. 11/670,736, filedFeb. 2, 2007.

BACKGROUND OF THE INVENTION

In some structures, it may be desirable to selectively adjust thesurface characteristics. As a basic example, most aircraft wings includeflaps, which may be engaged to modify the drag and lift characteristicsof the aircraft. Additionally, projectiles such as cruise missiles ofteninclude adjustable control surfaces to modify the trajectory of theprojectile in flight.

At the other end of the spectrum, the entire wing may be configured toadjust. For example, the Grumman F-14 Tomcat features a variablegeometry wing design. This variable geometry wing design provides theF-14 with one aerodynamic surface configuration suited to low velocityas well as another configuration for high velocity. A mechanical systemcontrols the disposition of the wings. Mechanically adjusting thecontrol surface, however, disrupts the airflow, reducing aerodynamicefficiency and undercutting the benefit of the functionality.

Various other schemes for extending and dynamically changing wing andcontrol surface configurations have been developed, but have variouslimitations. For example, many systems can only extend a relativelysmall amount before reaching a mechanical limit. In addition, many suchsystems create uneven airflow surfaces.

In addition to in-flight surface adjustments, an aerodynamic system mayrequire an in-flight surface geometry which would be inappropriate forstorage and/or launch of the system. For example, in projectiles whichare fired from a tube, the internal geometry of the launch mechanism mayplace constraints on the use of canards. As such, canards are sometimesconfigured to stow inside of or flush with the projectile for deploymentafter launch. As with mechanically adjusted wings, deployable canardsare generally actuated with mechanical systems, reducing reliability andincreasing cost.

SUMMARY OF THE INVENTION

Methods and apparatus for systems having deployable elements accordingto various aspects of the present invention comprise a system includinga deployable surface and an adaptive actuator including a polymer foam.In one embodiment, the system comprises a vehicle including a deployablewing comprising an exterior surface. The exterior surface may beadjusted by adjusting the shape, size, position, and/or orientation ofthe adaptive actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the following illustrative figures. In the followingfigures, like reference numbers refer to similar elements and stepsthroughout the figures.

FIG. 1 is a view of a projectile with a selectively adjustable controlsurface.

FIGS. 2A-B are views of a selectively adjustable control surface.

FIGS. 3A-B are views of a polymer foam having an exterior surface.

FIGS. 4A-C are views of a polymer foam having multiple positionalstates.

FIGS. 5A-B are views of a support module.

FIGS. 6A-B are views of an alternative support module.

FIG. 7 is a flowchart displaying operation of a selectively adjustablecontrol surface.

Elements and steps in the figures are illustrated for simplicity andclarity and have not necessarily been rendered according to anyparticular sequence. For example, steps that may be performedconcurrently or in different order are illustrated in the figures tohelp to improve understanding of embodiments of the present invention.

DETAILED DESCRIPTION

The present invention may be described in terms of functional blockcomponents and various processing steps. Such functional blocks may berealized by any number of techniques, technologies, and methodsconfigured to perform the specified functions and achieve the variousresults. For example, the present invention may employ variousmaterials, coatings, actuators, electronics, shape memory materials,airflow surfaces, reinforcing structures, and the like, which may carryout a variety of functions. In addition, the present invention may bepracticed in conjunction with any number of devices, and the systemsdescribed are merely exemplary applications. Further, the presentinvention may employ any number of conventional techniques for launchingvehicles, deforming materials, reinforcing materials, providing andcontrolling control surfaces, adjusting the surface area of a surface,and the like.

Methods and apparatus for an adjustable surface according to variousaspects of the present invention may be implemented in conjunction witha deployable element 100 of a vehicle. The methods and apparatus may beimplemented in conjunction with any system utilizing a deployableelement 100, however, such as a vehicle, propeller, turbine, or othersystem configured to translate and/or rotate. Referring to FIG. 1, adeployable element 100 according to various aspects of the presentinvention is implemented in conjunction with a projectile 112, in whichthe deployable element 100 comprises a deployable wing 104. In addition,the projectile 112 may comprise a control system 110 to selectivelycontrol the wing 104, such as to move at least a portion the wing 104.

The projectile 112 comprises a system that travels, rotates, and/ortranslates, such as a manned or unmanned vehicle. The projectile 112 maycomprise any appropriate system, such as a vehicle, rocket, missile,aircraft, guided or unguided bomb, submarine, propeller, turbine,artillery shell, or torpedo. In the present embodiment, the projectile112 comprises a missile, such as a military missile for delivering awarhead, or an unmanned aerial vehicle, such as a remotely controlledaircraft configured to perform reconnaissance missions and/or delivermunitions to a target. The projectile 112 may also be configured to flyat a variety of speeds, such as low subsonic speeds, for example toloiter over an area to be monitored, as well as high subsonic orsupersonic speeds, for example to cruise to a target area. Accordingly,the projectile 112 may include appropriate systems for the particularapplication or environment, such as guidance systems, reconnaissanceequipment, warheads, communications equipment, cargo bays, crewinterfaces, and propulsion systems.

The deployable element 100 may be configured to move or otherwise changestate. In the present exemplary embodiment, the deployable wing 104 isattached to the fuselage of the projectile 112 and at least partiallycontrols the flight of the projectile 112. The deployable wing 104comprises a surface for controlling the flight of the projectile 112,such as a wing, fin, stabilizer, aileron flap, slat, rudder, elevator,or other surface. In alternative embodiments, however, the deployableelement 100 may comprise any system or element that selectively moves.

In the present embodiment, the deployable wing 104 may be extended andretracted to adjust the surface area of the wing 104, for exampleaccording to the speed of the projectile 112. The wing 104 may beconfigured in any manner to facilitate the adjustment of the wing 104surface area, configuration, position, or size. In the presentembodiment, the wing 104 may be selectively extended and retracted inconjunction with an exterior surface 102 and an adaptive actuator 105.The exterior surface 102 comprises a surface exposed to airflow,exhaust, or the like for controlling the projectile 112, such as aconventional lift surface, control surface, or other surface configuredto interact with a fluid. The adaptive actuator 105 controls theconfiguration of the exterior surface 102. For example, referring toFIGS. 2A-B, the adaptive actuator 105 may be configured to define theexterior surface 102 of the deployable wing 104 in an extended position208. In the extended position 208, the wing length 204 and the exteriorsurface 102 area may be configured for low speed flight. The adaptiveactuator 105 may further be configured to define the exterior surface102 of the deployable wing 104 in a retracted position 206. In theretracted position 206, the wing length 204 and the exterior surface 102area may be configured for higher speed flight to enhance aerodynamicefficiency.

The exterior surface 102 of the present embodiment comprises theadjustable exterior surface of the deployable wing 104. The exteriorsurface 102 may be configured to selectively modify the aerodynamicproperties of the projectile 112, for example by changing theorientation, position, shape, and/or size of the exterior surface 102.In addition, the wing 104 may be adjusted for non-flight purposes, forexample to place the projectile 112 in a stowed position. In the presentembodiment, the exterior surface 102 may be moved between a fullyextended position 208, a fully retracted position 206, and intermediatepositions between the fully extended and fully retracted positions 208,206 to modify the aerodynamic properties of the exterior surface 102.For example, at low velocities, it may be desirable to configure thefirst exterior surface 102 for high lift. While increasing the effectivearea of the exterior surface 102 may increase drag as well as lift, atlow velocities the benefit of increased lift may outweigh the detrimentof increased drag. At high velocities, it may be desirable to configurethe exterior surface 102 for low drag. While decreasing the effectivearea of the exterior surface 102 may decrease lift as well as drag, athigh velocities the benefit of decreased drag may outweigh the detrimentof decreased lift. In alternative embodiments, the exterior surface 102may be otherwise modified, for example to adjust the cross-sectionalheight or length of the wing 104 or the angle of the wing 104 relativeto the fuselage, to fold and/or move the wing 104 for stowage, or tootherwise affect the properties of the projectile 112.

The exterior surface 102 may also include surface geometries configuredto modify the aerodynamic properties of the control surface 104. Forexample, the exterior surface 102 may include grooves configured toaffect the flow of air over the exterior surface 102. As anotherexample, the exterior surface 102 may be configured to use the flow offluid over the exterior surface 102 to generate force for lift orcontrol of the projectile 112. The exterior surface 102 may comprise anymaterial for facilitating airflow and adjustment of the size and/orshape of the exterior surface, such as cloth, plastic, metal, ceramic,and/or other appropriate materials. For example, the exterior surface102 may comprise a flexible skin or coating disposed over the exteriorof the wing 104 and configured to fold, unfold, stretch, and/or retractin response to the status of the adaptive actuator 105. In the presentembodiment, the exterior surface 102 comprises an exterior surface ofthe adaptive actuator 105, such that when the adaptive actuator 105extends and/or retracts, the exterior surface 102 extends and/orretracts accordingly. Further, the exterior surface 102 may be graded,as by abrading, surface treatment, and/or the like, or otherwise coatedso as to substantially eliminate surface porosity.

The adaptive actuator 105 defines and controls the configuration of theexterior surface 102. Further, the adaptive actuator 105 may provide atleast part of the force to move the elements of the deployable element100, for example to extend and/or retract the wing 104. The adaptiveactuator 105 may be implemented in any appropriate manner to deform, forexample in response to movement of the support module 108, to anindependent mover such as a pneumatic or hydraulic mover, mechanicalactuator, servo, motor, and/or to an actuating condition.

In the present embodiment, the adaptive actuator 105 defines theproperties of the exterior surface 102. The adaptive actuator 105 mayaffect the position, orientation, size, and/or shape of the exteriorsurface 102. The adaptive actuator 105 may be attached to the exteriorsurface 102 so that movement of the adaptive actuator 105 is translatedto the exterior surface 102. In one embodiment, the exterior surface 102is rigidly attached to the adaptive actuator 105, for example bysupports between the adaptive actuator 105 and the exterior surface 102.In another embodiment, the exterior surface 102 is a surface of theadaptive actuator 105, such that the exterior surface 102 is integratedinto the adaptive actuator 105. Alternatively, the exterior surface 102may engage the adaptive actuator 105, such as a coating applied to theexterior of the adaptive actuator 105. In the present embodiment, theadaptive actuator 105 includes a material configured to selectivelychange shape and/or size in response to a signal. The adaptive actuator105 may comprise, for example, a polymer foam 106, such as aconventional polymer foam or a shape memory polymer foam that changessize and/or shape in response to a signal or other control mechanism.The polymer foam 106 may be configured for reversible deformation orirreversible deformation.

The adaptive actuator 105 may support the exterior surface 102. Forexample, the exterior surface 102 may be supported by the polymer foam106, applied to the polymer foam 106, and/or integrated into the polymerfoam 106. In one embodiment, the exterior surface 102 comprises theouter surface of the polymer foam 106. As another example, the exteriorsurface 102 may comprise a coating applied to and/or formed on or in thepolymer foam 106. As yet another example, the exterior surface 102 maybe substantially flush against polymer foam 106.

By controlling the shape and/or size of the adaptive actuator 105, thesize and/or shape of the exterior surface 102 may be adjusted. Forexample, referring to FIGS. 3A-B, to extend the wing 104 for low speedflight, the polymer foam 106 may be extended away from the fuselage ofthe projectile 112 to the extended position 208 to increase the area ofthe wing 104. Conversely, to retract the wing 104 for higher speed, thepolymer foam 106 may be retracted to the retracted position 206 toreduce the area of the wing 104.

The adaptive actuator 105 may be configured for a particular actuationresponse time. For example, in a given application, such as a pursuitvehicle, it may be desirable to have a polymer foam 106 that isconfigured to deform relatively quickly to facilitate rapid accelerationand deceleration. In other applications, such as a weather monitoringaircraft, the polymer foam 106 may deform more slowly.

The adaptive actuator 105 may also be selected and/or configured for aspecified material property. For example, for a high velocity projectile112, the polymer foam 106 may be selected and/or configured to withstandhigh stresses and/or high fluctuations in temperature. For anapplication demanding low power consumption, the polymer foam 106 may beselected and/or configured to deform in response to a low power signal.In an application where the polymer foam 106 may experience significantvariations in temperature during operation, the polymer foam 106 may beselected and/or configured for low thermal expansion to maintain thesurface properties of the polymer foam 106 over the relevant temperaturerange.

Any appropriate adaptive actuator 105 may be utilized according toapplication and/or environment. In addition to various deformationprocesses and mechanisms, the adaptive actuator 105 may comprise variousmaterials, dimensions, and geometries, and may be selected according toany appropriate criteria, such as structural integrity, stiffness,strength, actuation power requirements, lateral expansion andcontraction characteristics, and/or thermal response characteristics.For example, the adaptive actuator 105 may comprise alloys such asnitinol. The adaptive actuator 105 may also comprise polymers such asurethane, styrene-butadiene, crystalline diene, norbornane, and/or thelike. The adaptive actuator 105 may be embedded with particles to modifythe material properties of the adaptive actuator 105. For example, theadaptive actuator 105 may be embedded with nanoparticles, such as C60molecules, to improve properties such as stiffness, strength, inflightheating rate, and/or thermal conductivity of the adaptive actuator 105.The adaptive actuator 105 may be selected and configured according toany appropriate criteria, including the material properties requirementsof the system, the behavior of a given material, durability, allowablevolumetric expansion, and/or the like.

The adaptive actuator 105 may be substantially porous. In the presentembodiment, the adaptive actuator 105 comprises polymer foam 106 that isa substantially porous material. Various polymer foam 106 materials mayachieve volumetric deformations of 400% or more without substantialcross-sectional deformation. The polymer foam 106 is shaped to provide adesired exterior surface configuration, such as an airfoil. The polymerfoam 106 is oriented to deform laterally with respect to the projectile112 fuselage in response to the relevant signal to extend or retract thewing 104. In addition, the polymer foam 106 is configured to exhibitminimal cross-sectional deformation so that the wing 104 cross-sectionremains substantially constant regardless of the extension or retractionof the wing 104. While shape memory polymer may be configured to achievereversible deformation of up to 20% of an initial length, polymer foamssuch as shape memory foams may be configured to achieve reversibledeformation of 400% of an initial length or more. A foam materialachieves much greater deformations than a non-porous material becausethe deformation mechanism within a foam material is primarily foam cellcollapse and expansion.

For example, referring now to FIGS. 4A-C, a cylindrical piece of polymerfoam 106 may have a first position 302 (FIG. 4A) and a second position304 (FIG. 4B). Comparing the first position 302 and the second position304, the circular cross section is substantially constant. Contrastingthe first position 302 and the second position 304, the length in thedirection of deformation is substantially different. The cylindricalpiece comprises polymer foam 106 configured to deform at least about50%, such as at least about 100%, 200%, 300%, or 400% along the axis ofdeformation. In one embodiment, the cylindrical piece may be comprisedof a shape memory material having a Poisson's ratio of about O.Accordingly, the cylindrical piece may be configured to provide asubstantially constant cross sectional area and a first and secondlength corresponding to the first and second position 302/304. Inanother embodiment, the cylindrical piece may comprise polymer foam 106configured for reversible deformation. Specifically, the cylindricalpiece may be configured to deform from a first position 302 to a secondposition 304 and back to a first position 302/306 (FIG. 4C).

The adaptive actuator 105 may respond to any appropriate signal, such asan electrical, optical, acoustic, mechanical, pneumatic, magnetic,thermal, chemical, or other suitable signal. In the present embodiment,the signal may be selected according to the polymer foam 106. Forexample, the polymer foam 106 may deform in response to a thermodynamiccondition such as temperature change, an electromagnetic condition suchas a magnetic field, or a chemical condition such as a specifiedreactive chemical.

For example, the adaptive actuator 105 may comprise a polymer foam 106such as shape memory foam configured to exhibit specific behavior inrelation to the glass transition temperature, Tg, of the material 106.The polymer foam 106 may be configured such that in the glassy state,the polymer foam 106 has the consistency and general characteristics ofa durable plastic. To the extent that Tg corresponds to the normaloperating conditions of the system 100 when stored and/or prior todeployment, the adaptive actuator 105 is highly durable. At temperaturesabove Tg, the polymer foam 106 may be deformed and the polymer foam 106may substantially retain the deformed shape. As the temperature of thepolymer foam 106 is decreased, the polymer foam 106 substantiallyretains the deformed shape. When the polymer foam's 106 temperature issubsequently raised above Tg, the polymer foam 106 returns to itsoriginal shape. This property may be described as hibernated elasticmemory in the rigid state.

For a specified electromagnetic condition, the adaptive actuator 105 mayexhibit specific behavior in relation to the potential difference, E,across the adaptive actuator 105. For instance, at voltages below E, theadaptive actuator 105 may have a first position or form 206. When thepotential difference across the adaptive actuator 105 is raised toexceed E, the adaptive actuator 105 may move to a different form orposition 208. An example of this type of material is artificial muscletissue.

The adaptive actuator 105 may also be configured to operate in relationto a specified magnetic field. For example, the polymer foam 106 mayassume one position 206 when a magnetic field is insubstantial or aparticular polarity and a second position 208 when the magnetic field isactivated or reversed. For example, alignment of ferromagnetic particleswithin the polymer foam 106 may cause desired deformation of the polymerfoam 106. Alternatively, the polymer foam 106 may respond to a specifiedcharge. For example, deformation of the polymer foam 106 may be inresponse to repulsive forces generated between particles of disparatematerials comprising the polymer foam 106 in the presence of anelectrostatic charge.

The adaptive actuator 105 may also be configured to operate in relationto a specified electric field. For example, the polymer foam 106 mayassume one position 206 when an electric field is insubstantial and asecond position 208 when the electric field is activated. For example,an electric field imparted via a plurality of capacitors or resistorsembedded within the polymer foam 106 may excite the polymer moleculesand heat the polymer foam 106 to a specified temperature.

In addition, the adaptive actuator 105 may respond to a particularchemical. When a specified chemical is applied to or sufficientlyinterspersed in the polymer foam 106, the polymer foam 106 may deformfrom a first position to a second position 208. For example, thedeformation may be caused by a thermodynamic component of the reactionbetween the specified chemical and the polymer foam 106. As anotherexample, the deformation may be caused by a volumetric differencebetween the polymer foam 106 prior to the reaction and the polymer foam106 after the reaction.

The control system 110 controls the operation of the adaptive actuator105 to control the deployment of the wing 104. For example, the controlsystem 110 may be configured to selectively actuate the polymer foam 106and/or the exterior surface 102. The control system 110 may comprise anindependent control system or may be integrated into other systems, suchas guidance and/or communications systems.

The control system 110 may control the deployable element 100 accordingto any criteria. For example, the control system 110 may control thedeployable element 100 in response to remote communications, sensedconditions, pre-programmed timing or conditions, and the like. Forexample, the control system 110 may be configured to approximate atrajectory based on guidance elements like an inertial guidance systemor a global positioning receiver, evaluate the current trajectory of theprojectile 112 based on the approximate trajectory and a desiredtrajectory, and actuate the control surface 104 accordingly. As anotherexample, the control system 110 may be configured to detectelectromagnetic radiation as reflected by a target and actuate thecontrol surface 104 accordingly. As yet another example, the controlsystem 110 may be configured to receive instructions from a remotesource or determine an elapsed time and actuate the control surface 104accordingly.

The control system 110 may be configured to operate the adaptiveactuator 105 in any appropriate manner. In one embodiment, the controlsystem 110 may include a control interface substantially integrated intothe polymer foam 106. For example, the control interface may comprise awire mesh configured for Ohmic heating at least partially enclosed bythe polymer foam 106. As another example, the control interface maycomprise a packet of chemicals configured to selectively provide anexothermic reaction in response to a signal or condition. As yet anotherexample, the control interface may comprise capacitor plates embeddedwithin various segments of the adaptive actuator 105 and configured toinduce heating of the adaptive actuator 105 by virtue of the capacitor'selectric field. Further, the control interface may be configured toexpose the adaptive actuator 105 to a specified wavelength ofelectromagnetic radiation. Alternatively, the control interface may besubstantially separated from the polymer foam 106. For example, thecontrol interface may comprise connections to provide electrical,pneumatic, magnetic, or other signals to the polymer foam 106. Inanother embodiment, the control interface may be an inherent feature ofthe operating environment of the projectile 112, such as the ambienttemperature at 10,000 feet, such that the adaptive actuator 105 deploysautomatically in response to the relevant ambient temperature.

The configuration of the control system 110 may be substantially relatedto the material comprising the adaptive actuator 105. For example, somematerials such as shape memory foams may deform in response to aspecific actuation method such as increasing the temperature of thematerial, imparting a magnetic field within the material, and/or thelike. Accordingly, the control system 110 may be configured toaccommodate actuation of such materials. Other materials may be deformedvia tensile forces, such as may be imparted by an expansive member, suchas the support module 108, enclosed by the material. Accordingly, thecontrol system 100 may be configured to adjust the properties of such anexpansive member to adjust the properties of the adaptive actuator 105.Further, some adaptive actuator 105 materials may be suited to aplurality of actuation mechanisms. For example, some polymer foams 106may respond more efficiently to an expansive member when the polymerfoam 106 is heated to a specified temperature. Accordingly, the controlsystem 110 may be configured to heat the polymer foam 106 to a specifiedtemperature as well as actuating the expansive member.

The deployable element 100 may be coupled to another portion of theprojectile 112 in any appropriate manner, such as rigidly, resiliently,or movably. For example, the wing 104 may be integrated into theprojectile 112 or attached using conventional connectors, such asrivets, adhesives, welds, and the like. Referring again to FIG. 1, inone embodiment, the present wing 104 is disposed on a support module108. The support module 108 is connected to the projectile 112 fuselage,and the adaptive actuator 105 is supported and/or actuated by thesupport module 108.

The support module 108 may comprise various materials, dimensions, andgeometries. The support module 108 may further be configured accordingto any appropriate criteria relevant to the application and/orenvironment, such as the intended durability of the projectile 112, theintended environment in which the projectile 112 is to operate, theoperational stresses within the wing 104, the maximum allowable mass ofthe support module 108, the size and operating properties of theprojectile 112, the dimensions and geometries of the exterior surface102, the extent to which the support module 108 is to lift and/or dragto the projectile 112, and/or the like.

The support module 108 may perform various functions, includingconnecting the wing 104 to the projectile 112 fuselage. For example, thesupport module 108 may support the polymer foam 106 and/or impartdeformation within the adaptive actuator 105. In addition, the supportmodule 108 may mitigate deflection, such as may be caused by gravity,drag, lift, etc., in operation of the adaptive actuator 105. Further,the support module 108 may maintain the surface geometry of the adaptiveactuator 105.

Referring to FIGS. 5A-B, the support module 108 may include any elementsfor connecting the wing 104 to the projectile 112 fuselage and any otherrelevant functions, such as a bearing couple 502, a module cover 210,and a brace 504. The bearing couple 502 may couple the support module108 and the polymer foam 106 to the projectile 112 fuselage. The modulecover 210 covers the connection point between the wing and theprojectile fuselage and/or provides aerodynamic properties to the wing104. The brace 504 provides structural support to the polymer foam 106.

The support module 108 may be configured to couple the wing 104 to theprojectile 112 fuselage in any suitable manner. For example, in thepresent embodiment, the support module 108 is movably connected to theprojectile 112 fuselage to facilitate movement of the wing 104 from astowed position to a flight position. For example, the bearing couple502 may be configured to selectively deploy the wing 104 from theprojectile 112 fuselage. In the present embodiment, the bearing couple502 comprises a substantially hollow, substantially cylindrical portionof the support module 108 configured to receive a corresponding pinstructure (not shown) on the projectile 112 fuselage such that thesupport module 108 may selectively rotate about the pin structure. Theprojectile 112 may be configured to omit continuous spars or otherstructural members extending through the fuselage so the wings can befolded into the stowed position.

The bearing couple 502 may comprise a low-friction internal surface,such as the low friction surface sold under the trademark Teflon®, ballbearings, liquid and/or semi-liquid lubricants, and/or the like. Asanother example, the bearing couple 502 may comprise notches and/orflanges configured to restrict rotation of the support module 108 aboutthe projectile 112. As yet another example, the bearing couple 502 maybe configured to deploy the wing 104 in response to drag forces exertedon the wing 104. The projectile 112 may also be configured to deploy thewing 104. For example, the projectile 112 may include a mechanism, suchas a motor or spring, to selectively rotate the wing 104 around thebearing couple 502 to deploy and/or retract the wing 104.

In addition, referring again to FIG. 1, the projectile 112 fuselage maybe configured to accommodate the wing 104 in a stowed position, such asincluding a recess 114 formed in the exterior of the fuselage. Therecess 114 may be configured to allow stowage of the wing 104substantially flush with or substantially within the projectile 112. Forexample, the recess 114 may be an indentation along the side of theprojectile 112 and configured to receive the wing 104. Stowing the wing104 may protect the wing 104, facilitate firing the projectile 112 froma barrel, achieve a specific aerodynamic property, and/or the like.

The recess 114 may substantially conform to the exterior surface 102 ofthe wing 104. As another example, the recess 114 may substantiallyaccommodate the polymer foam 106 in a given position. The recess 114 maycomprise a substantially distinct portion of and comprise the samematerial as the projectile 112. Alternatively, the recess 114 may be adistinct component coupled to the projectile 112 and comprise asubstantially disparate material. The recess may be configured accordingto any relevant criteria, such as the operating environment of theprojectile 112, chemical interaction between the various materials ofthe system, required durability of the recess 114, and/or the like.

The module cover 210 of the support module 108 covers the connectionbetween the wing 104 and the projectile 112 fuselage. The module cover210 may be configured to provide an aerodynamic surface regardless ofthe position of the polymer foam 106. For example, the module cover 210of the support module 108 may provide a portion of the wing 104 surface.As another example, the module cover 210 of the support module 108 maycomprise a minimal portion of the exterior surface 102 of the controlsurface 104. In this embodiment, the component of either lift and/ordrag force as a consequence of the module cover 210 may be negligible.

The support module 108 may further include the brace 504 to support thepolymer foam 106. In some embodiments, the brace 504 may be omitted, forexample if the polymer foam 106 exhibits adequate structuralcharacteristics for the intended application. The brace 504 may beconfigured in any appropriate manner to support the adaptive actuator105 and/or other elements of the wing 104, such as to add stiffnessand/or durability to the wing 104. In the present embodiment, thepolymer foam 106 substantially encases the brace 504.

The brace 504 may also be configured to move with the polymer foam 106as it deforms. For example, the brace 504 may include movable elements.In the present embodiment, referring again to FIGS. 5A-B, the brace 504comprises a slidably coupled member 510 configured to assume a retractedsupport position 506 corresponding to the retracted position 206 of thepolymer foam 106 and an extended support position 508 corresponding tothe extended position 208 of the polymer foam 106. The slidably coupledmember 510 may be configured to slide in conformance with thedeformation of the polymer foam 106. For example, the slidably coupledmember 510 may be configured to couple to the polymer foam 106 such thatthe deformation of the polymer foam 106 imparts a sliding force on theslidably coupled member 510, causing the slidably coupled member 510 tomove with the polymer foam 106. Further, the slidably coupled member 510may be configured to couple to the polymer foam 106 such that sliding ofthe slidably coupled member 510 imparts deformation within the polymerfoam 106. As another example, the slidably coupled member 510 may beindependently moved, as by a rack and pinion gear, a solenoid, anelectric motor, and/or other motive force.

In an alternative embodiment, the brace 504 may comprise a plurality ofnesting concentric elements, such as a plurality of hollow structuralsections configured to slide substantially concentrically with respectto each other. Referring to FIG. 6A-B, the brace 504 may includeconcentric sections 610 configured to support the adaptive actuator 105and/or other elements of the wing 104, such as to add stiffness and/ordurability to the wing 104. The concentric sections may also beconfigured to move with the polymer foam 106 as the polymer foam 106deforms. For example, the concentric section 610 may assume a retractedsupport position 606 corresponding to the retracted position 206 of thepolymer foam 106 and an extended support position 608 corresponding tothe extended position 208 of the polymer foam. More specifically, in theretracted support position 606, at least one element of the concentricsections 610 at least partially nests within another section. In theextended support position 608, the concentric section 610 extendsoutward from the other section to extend the brace 504.

To accommodate movement of the alternative brace 604 implementationbetween a retracted support position 606 and an extended supportposition 608, the nesting polyhedrons may comprise bearings and/or othersystems and material configured to reduce friction and/or guide movementamong the various elements of the alternative brace 604 implementation.In the present alternative embodiment, at least one interface of eachconcentric section 610 is outfitted with a bearing 620 and a groove 625configured to receive the bearing. Movement of the concentric sectionsmay be constrained to the interface between the bearing 620 and thegroove 625 and friction may be predictably maintained.

The interface between the bearing 620 and groove 625 may comprise alow-friction internal surface such as the low-friction surface soldunder the trademark Teflon®, ball bearings, liquid and/or semi-liquidlubricants, and/or the like. Further, the interface may comprise notchesand/or flanges configured to restrict movement of the concentric sectionwith respect to each other.

The slidably coupled member 510, 610 may comprise one or more structuresconfigured to stow and deploy within a fixed portion of the supportmodule 108. For example, the slidably coupled member 510, 610 maycomprise one or more rectangular pieces configured to extend andretract. As another example, the slidably coupled member 510, 610 maycomprise one or more linkages configured to extend and retract.

In operation, referring to FIG. 7, the control system 110 may controlthe deployment of the wing 104 and/or the polymer foam 106 according todesired flight characteristics. For example, the projectile 112 may bestowed with the wing 104 rotated into the recess 114 to reduce theoverall size of the projectile 112 and resist damage (710).Alternatively, the wing 104 may be fixed to the fuselage in the flightposition.

The projectile 112 may be launched with the wings 104 deployed forflight, such as from a runway. The wings 104 may be deployed from thestowed position in any suitable manner, such as manually orautomatically (712), and the projectile may then be launched (714).Alternatively, the projectile 112 may be launched with the wings 104 inthe stowed position, for example from a gun barrel or a submarine, andthe wings 104 may deploy after launch. The wings 104 may deploy at anyappropriate time after launch, such as immediately after clearing thegun barrel or the water, after a time delay, or in response to a signalfrom the control system 110. Upon deployment, the wings 104 move to aflight position. In the present embodiment, the wings 104 rotate aroundthe bearing couple 502 to move into the flight position. In addition,the wings 104 may be locked into position for flight.

During flight, the control system 110 may control the exterior surface102 of the wings 104 via actuation of the adaptive actuator 105. Forexample, the control system 110 may reduce airspeed by reducing theengine output (716) and, to maintain lift, extend the wings 104. Thecontrol system 110 may provide the relevant signal to the adaptiveactuator 105 and/or the support module 108. In the present embodiment,the polymer foam 106 responds by deforming outwardly away from theprojectile 112 fuselage (718), thus extending the wing 104 and creatingadditional exterior surface 102 area (722). The polymer foam 106 mayextend longitudinally without significant deformation in the crosssection of the polymer foam 106. As the wing 104 extends, the brace 504may extend as well (720), providing support for the additional length ofthe wing 104. Conversely, the wing 104 may be retracted. In addition,the wing 104 may be deformed for other purposes, such as to control thepath of the projectile and the like.

The use of an adaptive actuator 105 comprised of polymer foam 106 mayhave a number of consequences with respect to operation of the system.For example, the polymer foam 106 may be configured to have a firstposition wherein the shape memory foam has a first length and a secondposition wherein the shape memory foam has a second length four timesgreater than the first length. In the event that the shape memory foamis deformed pursuant to modification of the wing length 204 and thesupport structure 510, 610 is configured to expand by a factor of three,the shape memory material would be in compression during all phases ofdeployment. Being in compression may substantially reduce the likelihoodof tearing the adaptive actuator 105 or exterior surface 102 due tolocalized tensile stresses.

The particular implementations shown and described are illustrative ofthe invention and its best mode and are not intended to otherwise limitthe scope of the present invention in any way. Indeed, for the sake ofbrevity, conventional manufacturing, connection, preparation, and otherfunctional aspects of the system may not be described in detail.Furthermore, the connecting lines shown in the various figures areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. Many alternative or additionalfunctional relationships or physical connections may be present in apractical system.

In the foregoing description, the invention has been described withreference to specific exemplary embodiments; however, it will beappreciated that various modifications and changes may be made withoutdeparting from the scope of the present invention as set forth herein.The description and figures are to be regarded in an illustrativemanner, rather than a restrictive one and all such modifications areintended to be included within the scope of the present invention.Accordingly, the scope of the invention should be determined by thegeneric embodiments described herein and their legal equivalents ratherthan by merely the specific examples described above. For example, thesteps recited in any method or process embodiment may be executed in anyorder and are not limited to the explicit order presented in thespecific examples. Additionally, the components and/or elements recitedin any apparatus embodiment may be assembled or otherwise operationallyconfigured in a variety of permutations to produce substantially thesame result as the present invention and are accordingly not limited tothe specific configuration recited in the specific examples. Benefits,other advantages and solutions to problems have been described abovewith regard to particular embodiments; however, any benefit, advantage,solution to problems or any element that may cause any particularbenefit, advantage or solution to occur or to become more pronounced arenot to be construed as critical, required or essential features orcomponents.

As used herein, the terms “comprises”, “comprising”, or any variationthereof, are intended to reference a non-exclusive inclusion, such thata process, method, article, composition or apparatus that comprises alist of elements does not include only those elements recited, but mayalso include other elements not expressly listed or inherent to suchprocess, method, article, composition or apparatus. Other combinationsand/or modifications of the above-described structures, arrangements,applications, proportions, elements, materials or components used in thepractice of the present invention, in addition to those not specificallyrecited, may be varied or otherwise particularly adapted to specificenvironments, manufacturing specifications, design parameters or otheroperating requirements without departing from the general principles ofthe same.

The present invention has been described above with reference to apreferred embodiment. However, changes and modifications may be made tothe preferred embodiment without departing from the scope of the presentinvention. These and other changes or modifications are intended to beincluded within the scope of the present invention, as expressed in thefollowing claims.

1. A vehicle comprising: a fuselage; and a configurable control surfaceconnected to the fuselage; wherein the control surface has aconfigurable external shape; and wherein the configurable controlsurface includes: a brace; and a polymer foam attached to and overlyingthe brace, wherein the polymer foam selectively changes shape as part ofconfiguring of the configurable external surface, and wherein the braceprovides structural support for the polymer foam.
 2. The vehicle ofclaim 1, wherein the control surface is a wing.
 3. The vehicle of claim1, wherein the polymer foam is a shape memory polymer material.
 4. Thevehicle of claim 1, wherein an actuator of the control surfaceselectively extends and retracts the polymer foam.
 5. The vehicle ofclaim 4, wherein the actuator includes the polymer foam.
 6. The vehicleof claim 4, wherein the actuator includes the brace.
 7. The vehicle ofclaim 1, wherein the brace is selectively movable between a retractedsupport position and an extended support position.
 8. The vehicle ofclaim 7, wherein the brace includes multiple elements slidable withrespect to each other.
 9. The vehicle of claim 1, wherein the controlsurface includes a support module that supports the actuator.
 10. Thevehicle of claim 1, wherein the external surface is a non-porous surfaceof the polymer foam.
 11. The vehicle of claim 1, wherein the polymerfoam maintains a substantially constant cross section during theconfiguring of the external surface.
 12. A method of configuring acontrol surface of an air vehicle, the method comprising: providing thecontrol surface with a polymer foam attached to an underlying brace thatis connected to an airframe of the air vehicle, and that providesstructural support for the polymer foam; and configuring the controlsurface by using changing shape of the polymer foam.
 13. The method ofclaim 12, wherein the polymer foam covers an external surface of thecontrol surface; and wherein the configuring includes changing a surfacearea of the external surface.
 14. The method of claim 12, wherein theconfiguring includes extending and retracting the polymer foam.
 15. Themethod of claim 12, wherein the control surface is a wing.
 16. Themethod of claim 12, wherein the polymer foam is a shape memory polymermaterial.
 17. The method of claim 12, wherein the configuring includesselectively moving the brace between a retracted support position and anextended support position.
 18. The method of claim 17, wherein the braceincludes multiple elements slidable with respect to each other; andwherein the configuring includes sliding one of the elements relative toanother of the elements.
 19. The method of claim 18, wherein the polymerfoam maintains a substantially constant cross section during theconfiguring.